candlepower (cp)

The candlepower (cp) is an obsolete unit of luminous intensity. One candlepower (cp) was originally defined (1860) as the amount of light given off by a pure spermaceti candle (made from the fat of the sperm whale) weighing one sixth of a pound and burning at a rate of 120 grains per hour. Other definitions followed later. Today, if the term candlepower is used it is exactly equivalent to the candela.